uapi drm/armada_drm.h: use __u32 and __u64 instead of uint32_t and uint64_t

uapi drm/armada_drm.h: use __u32 and __u64 instead of uint32_t and uint64_t

These are defined in linux/types.h or drm/drm.h. Fixes
user space compilation errors like:

drm/armada_drm.h:26:2: error: unknown type name ‘uint32_t’
  uint32_t handle;
  ^~~~~~~~

Signed-off-by: Mikko Rapeli <mikko.rapeli@iki.fi>
Cc: Emil Velikov <emil.l.velikov@gmail.com>
Cc: Gabriel Laskar <gabriel@lse.epita.fr>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Rob Clark <robdclark@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20170806164428.2273-33-mikko.rapeli@iki.fi